From: Michael Matz <matz@suse.de>
To: Richard Guenther <rguenther@suse.de>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] Rewrite TRUTH_NOT_EXPR as BIT_{NOT,XOR}_EXPR
Date: Tue, 19 Jul 2011 16:37:00 -0000 [thread overview]
Message-ID: <Pine.LNX.4.64.1107191733560.25049@wotan.suse.de> (raw)
In-Reply-To: <alpine.LNX.2.00.1107191233370.810@zhemvz.fhfr.qr>
Hi,
On Tue, 19 Jul 2011, Richard Guenther wrote:
> *************** forward_propagate_comparison (gimple stm
> *** 1164,1170 ****
> }
> /* We can propagate the condition into a statement that
> computes the logical negation of the comparison result. */
> ! else if (gimple_assign_rhs_code (use_stmt) == TRUTH_NOT_EXPR)
> {
> tree type = TREE_TYPE (gimple_assign_rhs1 (stmt));
> bool nans = HONOR_NANS (TYPE_MODE (type));
> --- 1165,1174 ----
> }
> /* We can propagate the condition into a statement that
> computes the logical negation of the comparison result. */
> ! else if ((gimple_assign_rhs_code (use_stmt) == BIT_NOT_EXPR
> ! && TYPE_PRECISION (TREE_TYPE (lhs)) == 1)
> ! || (gimple_assign_rhs_code (use_stmt) == BIT_XOR_EXPR
> ! && integer_onep (gimple_assign_rhs2 (use_stmt))))
In XOR case you want either precision==1 or integer_all_onesp (the fixed
variant), otherwise it's no inversion.
Ciao,
Michael.
next prev parent reply other threads:[~2011-07-19 15:38 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-18 14:48 Richard Guenther
2011-07-19 11:43 ` Richard Guenther
2011-07-19 16:37 ` Michael Matz [this message]
2011-07-20 9:43 ` Richard Guenther
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